Everything Science Grade 10

10.3 CHAPTER 10. SOUND

Intensity of sound [NOT

IN CAPS]

ESADE

Intensity is one indicator of amplitude. Intensity is the energy transmitted over a unit of

area each second.

The unit of intensity is thedecibel(symbol: dB).

Source Intensity(dB) Times greater than hearing threshold

Rocket Launch 180 1018

Jet Plane 140 1014

Threshold of Pain 120 1012

Rock Band 110 1011

Factory 80 108

City Traffic 70 107

Normal Conversation 60 106

Library 40 104

Whisper 20 102

Threshold of hearing 0 0

Table 10.3: Examples of sound intensities.

Vuvuzelas feature prominently at soccer

events in South Africa. The intensity of the

sound from a vuvuzela depends on how

close you are. In Table 10.3 you can see how

the intensity differs.

Vuvuzelas in action

Photo by Dundas Football Club on

Flickr.com

176 Physics: Waves, Sound and Light